7 piperazinofluorans

ABSTRACT

AN EXCELLENT PRESSURE SENSITIVE COPYING SHEET IS PROVIDED BY APPLYING AS A COLOR FORMER CERTAIN ENCAPSULED FLUORAN COMPOUNDS, I.E. FLUORAN COMPOUNDS LINKING IN THE 7-POSITION WITH AT LEAST ONE OF THE TWO NITROGEN ATOMS IN A PIPERAZINE RING AND HAVING A DIALKYLAMINO GROUP IN THE 3-POSITION TO EITHER A SINGLE SHEET OR TO THE UPPER LEAF OF A PRESSURE SENSITIVE PAPER. THE COLOR FORMER IS SOLUBLE IN AROMATIC SOLVENTS AND ALSO HAS EXCELLENT LIGHT FASTNESS.

United States Patent Oflice 3,825,544 Patented July 23, 1974 3,825,544 7PIPERAZINOFLUORANS Mutsuo Terayama and Kenji Yamamoto, Osaka, Japan,assignors to Yamamoto Kagaku Gosei Kabushiki Kaisha N Drawing. FiledDec. 15, 1971, Ser. No. 208,432 Claims priority, application Japan, Dec.15, 1970, 45/112,052 Int. Cl. C07d 51/70 U.S. Cl. 260-268 PC 5 ClaimsABSTRACT OF THE DISCLOSURE An excellent pressure sensitive copying sheetis provided by applying as a color former certain encapsuled fluorancompounds, i.e. fluoran compounds linking in the 7-position with atleast one of the two nitrogen atoms in a piperazine ring and having adialkylamino group in the 3-position to either a single sheet or to theupper leaf of a pressure sensitive paper. The color former is soluble inaromatic solvents and also has excellent light fastness.

BACKGROUND OF THE INVENTION Basically, pressure sensitive copying sheetconsists of two sheets of paper, an upper leaf and a lower leaf, thelower surface of the upper leaf being coated with minute capsulescontaining a color reactive achromatic substance (hereinafter called acolor former) dissolved in a low volatile solvent and the upper surfaceof the lower leaf being coated with a solid acid, such as acid clay,zeolite, bentonite, attapulgite and phenolic compound, etc. When thelower surface of the upper leaf and upper surface of the lower leaf areput together and pressure is applied to the upper surface of the upperleaf by handwriting or typing, the capsules under pressure are brokenand the color former contained therein is adsorbed by the solid acid onthe upper surface of the lower leaf to develop a color, and thereby theobject of copying is attained.

There is also a type of pressure sensitive copying sheet having amechanism to develop a color when a regional pressure is exerted upon asheet of paper holding capsules, which contain a color former, and asolid acid on or within it. However, such type is quite similar to thefirstmentioned pressure sensitive copying paper (consisting of twosheets of paper, an upper and lower leaf) with respect to the mechanismof developing a color, and thus the same color former can be used forboth types. And any of the above-mentioned facts belongs to theprior-known arts.

conventionally, a number of compounds have been known to be useful asthe color former, such as lactones, i.e. crystal violet lactone andmalachite green lactone; thiazine compounds, i.e. benzoyl leucomethyleneblue; and other leucoauramine and spiropyran compounds, and others.

In most of the pressure sensitive copying sheets now in practical use,crystal violet lactone and benzoyl leucomethylene blue, both of whichdevelop a blue color, are used as the main color former. But the blueimage due to these color formers is not suitable for recopying by Xeroxor diazo system. It has therefore been hoped for to find out somesolution for this defect. This defect can be solved by obtaining a blackimage in two ways: (1) to employ a black color former, or (2) to employtwo or more color formers in combination for synthesizing a black image.

SUMMARY In accordance with the invention, an excellent pressuresensitive copying paper can be obtained by using a new and novel colorformer which is very advantageous in obtaining a black image, ofieringsuperiority not only in the speed of color development, the shade, andthe light resistance of the color developed, and the solubility but alsoin the simplicity of the manufacturing method and the low cost. The newand novel color former used in the present invention all develop intoeither black or red. One which develops into black can be used alone,while the other which develops into red can advantageously produce ahighly stabilized black image when mixed with one other color formerwhich develops into green (for example,3-diethylamino-7-benzylaminofluoran (see Canadian Pat. No. 814,948)).

The color former used in the present invention can be represented by thefollowing general formulae (I) and (II).

wherein R R and R represent methyl or ethyl, and R and R representhydrogen, methyl group, or halogen.

R Ra Ra R O 4 0 1 B4 CH CH N R2 N/ N R:

I\ CHz CH/B I\ O O C=O C=0 wherein R R R and R are the same as in thegeneral formula (I).

That is to say, we have found that the fluoran compounds linking in the7-position with at least one of the two nitrogen atoms in a piperazinering and having a dialkylamino group in the 3-position can become theblack and red color formers which are distinguished in all of the colordeveloping speed, the shade and the light resistance of the colordeveloped and the solubility and that they can be readily synthesized bythe process shown by the following reaction formula.

zmo-Q-mn znrcmomnr DETAILED DESCRIPTION The following are typicalexamples of the novel color former.

3-Diethylamino-7-(N'-paramethoxyphenyl) piperazinofluoran (IV) (III)This compound (IV) is a white crystal obtained by condensing 2 parts ofortho-(4-diethylamino-2-hydroxybenzoyl)benzoic acid (V) and 3 parts ofN,N-di(paramethoxyphenyDpiperazine (VI) in concentrated sulfuric acidand having a melting point of 237 to 240 C. It has the characteristicswhich are highly advantageous for the preparation of the pressuresensitive copying sheet, such as the rapid development into a black orblackish red color in the presence of a solid acid, and the excellentlight resistance of the color developed as well as the high solubilityin the solvent.

/N OH CzHa COOH H2 1 (VI) The compound (VI) can be readily obtained byrefluxing under heat paraanisidine and dibromoethane in the presence ofsodium carbonate.

CH 0%]; /o /O N/ 2 5 Ha Ha 2H: CzHs HTIE O O (VII) is a white crystalobtained by condensing 4 parts of (V) and 3 parts of (VI) inconcentrated sulfuric acid and having a melting point of 265 to 270 C.It also has the characteristics which are highly advantageous for thepreparation of the pressure sensitive copying sheet, such as the rapiddevelopment into a black or blackish red color in the presence of solidacid, and the excellent light resistance of the color developed as wellas the high solubility in the solvent.

C2H5 CH3 CH3 CzHs Hz Ha cz s C 2 5 (VIII) (VIII) is a white crystalobtained by condensing 2 parts of (V) and 1 part of (VI) in concentratedsulfuric acid and having a melting point of 210 to 215 C. This alsorapidly develops into a dark red color in the presence of a solid acid,has an excellent light resistance after developing into a color, anddissolves well in the solvent.

The present invention is further illustrated by the following examples.

Example 1 g. of gelatin and 60 g. of gum arabic were dissolved in 50 ml.of water of 40 C. On the other hand, 4 g. of 3- diethylamino 7 (Nparamethoxyphenyl)piperazinofluoran (IV) was dissolved in 120 g. ofdiphenyl chloride, and then this solution was added to theabove-mentioned aqueous solution of gelatin and gum arabic and perfectlydispersed into an emulsion by a homo-mixer. Water of 50 C. was addeduntil its volume became 2,000 ml. in total, followed by ml. of 10percent acetic acid. While stirring, water of 50 C. was further addeduntil the total weight became 4 kg., and the stirring was continued fora period of an hour. While still stirring, the solution was cooled downto below 10 C. with ice water, and 10 percent caustic soda was addeduntil a pH of 9, was reached, and gradually returned to roomtemperature. The product was applied onto the lower surface of the upperleaf and dried. 0n the other hand, a solid acid such as acid clay orphenolic compounds, etc. was applied onto the upper sur face of thelower leaf.

When copying was carried out with the upper and lower leaves thusprepared, a black or blackish red image rapidly developed, which showedan excellent light resistance.

Example 2 4 g. of N,N'-bis(3'-diethylaminofluoranyl)piperazine (VH) wasdissolved in g. of diphenyl chloride, which solution was then treated inthe same way as in Example 1 to obtain the pressure sensitive copyingsheet.

When copying was carried out with this copying sheet, a black orblackish red image rapidly developed, which showed an excellent lightresistance.

Example 3 Example 4 4 g. of N,N'-bis(3-diethylaminofiuoranyl)piperazine(VII) was dissolved in 120 g. of diphenyl chloride. By treating this inthe same way as in Example 1, an aqueous dispersion of minute capsuleswas obtained. This was sprayed and dried into a powder of minutecapsules, which was mixed with and dispersed in a 4 percent xylenesolution of p-phenylphenol formaldehyde condensate. And this dispersedsolution was applied onto a sheet of paper and dried. When a regionalpressure was exerted on this coated sheet of paper, it immediatelydeveloped a black image, which showed an excellent light resistance.

Example 4 g. of N,N-bis(3'-diethylamino-6'-methylfluoranyl) piperazine(VIII) was dissolved in 120 g. of diphenyl chloride.

By treating this solution in the same way as in Example I, an aqueousdispersion of minute capsules was obtained. This was mixed with 8 g. offine powder of pphenylphenol formaldehyde condensate to disperse thelatter therein, and 40 g. of pulp was further added thereto. Then thedispersion was diluted with water until the final solid content became0.5 percent. Then the product was run onto a Fourdrinier screen to bemade into a sheet of paper. When a regional pressure was exerted on thissheet of paper, it immediately developed a black image with an excellentlight resistance.

Although diphenyl chloride was used as a solvent in the foregoingexamples, the same pressure sensitive copying paper can be obtainedwithout problem with the use of other aromatic solvent. These aromaticsolvents of low volatility include lower alkyl diphenyls, such asmethyl-, ethyland propyl diphenyl, and higher alkyl benzenes, such asdodecyl-, decyland octyl benzene, having a boiling point of above 150 C.If the boiling point of the solvent is at least 150 C., it hassufiicient low volatility according to the invention.

The solid acid functions as an electron acceptive adsorbent. In place ofthose used in the previous examples zeolite, bentonite, attapulgite andSilton (manufactured and saled by Mizusawa Chemical Company Ltd.) can beused with excellent results.

What is claimed is:

1. A fluoran of the formula wherein each of R and R is methyl or ethyl;each of R and R is hydrogen, methyl or halogen; and A is either l 0 R4 la 4 s or V References Cited UNITED STATES PATENTS 5/1969 Orita 260335DONALD G. DAUS, Primary "Examiner US. Cl. X.R.

1l736.2; 260268 B1, 268 PA, 518 R UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent NO- 3,825,544 Dated July 23. 1974Inventor(S) Mutsuo Terayama and Kenji Yamamoto It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 2, Formula 1:

CH CH CH -CH' 2 2 2 Z N N should read Column 2, Formula II: The formulashould read as follows:

Column 4, line 68: "N,N-bis" should read --N,N'bis--,

" (10-59) uscoMM-oc 60376-P69 I.I.S. GOVIINIENT PRINTING OFFICE 2 1.,I-l3,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,825,544 Dated July 23, 1974 Inventor(S) Mutsuo Terayama and KenjiYamamoto Page 2 It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 6, line 20: The second formula should read as follows: R

Signed and sealed this 6th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attest ing 0f ficer and Trademarks FORM P0-105O (10-69) USCOMM-DC 60376-P69 I.I.S.GOVERNMENT PRINTING OFFICE I"! 0-86-334,

